[Newphoto]

Hello. I am new to photography, learning. I was doing some photography for a friends Bday and I rented the 580exII, I have never used and external flash before and told to just attach it and go.
I am using the entry level canon eos rebel xt 8meapixels. My problem was that when I did shoot it would flash, but when Itried to shoot again the flash would not fire. So out of 4 shots it fires once, I missed some good moments. I am sure its my fault operator error, I guess I don't understand the recycle rate? I thought it would just fire when I shoot, no matter how fast. Also the screen constantly blinks, is that normal? and the Pilot light stays red? Basically I want the flash to fire when I shoot, every time. and I would like to control the amount of flash output it gives, a lot the photos seem underexposed. So ANY help you can offer this very frustrated amateur would be appreciated.